Roof-framings tool



No. s|4,|44. Patented Nbv. I5, 1898. a. c. THOMPSON.

ROOF FRAMING TOOL.

(Application filed May 27, 1896.)

(N6 Model.)

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THE NORRKS warns on. PHOTO-LIYHD" WASHINGTON, n. c.

UNITED STATES PATENT OFFICE.

GEORGE CRANE THOMPSON, OF SALINAS, CALIFORNIA.

ROOF-FRAMING toot.

srEoI'rIcA'rIoN forming part of Letters Patent 1%. 614,144, datedNovember 15, 1898.

Application filed May 27, 1896. Serial No. 593,306. (No model.)

To all whom it Wtay concern:

Be it known that I, GEORGE CRANE THOMP- SON, a citizen of the UnitedStates, residing at Salinas, in the county of Monterey and State ofCalifornia, have invented a new and useful Roof-Framing Tool, of whichthe following is a specification.

My invention relates-to a roof-framin g tool or square designed toindicate the lengths and terminal cuts or bevels of common,hip-andvalley, and jack rafters when the rise per foot of the roof isknown.

Further objects and advantages of this invention will appear in thefollowing description, and the novel features thereof will beparticularly pointed out in the appended claim.

In the drawings, Figure 1 is a side view of a square embodying myinvention, a miterbevel being shown indotted lines applied in theoperative position thereto. Fig. 2 is a view of the opposite side of thesquare.

Similar letters of reference indicate corresponding parts in bothfigures of the drawings.

The tool embodying my invention is pref erably constructed in the formof a forty-fivedegree triangle wherein one of the angles is ninetydegrees. Upon one of the sides or perpendicular arms A of the triangleis a scale having a column of figures a, indicating in inches difierentrises per foot of runas, for instance, 2, 3, 4, &c.a contiguous column aof numerals indicating in inches the relative lengths of raftersarranged at the several pitches corresponding with a foot run and thegiven rise in inches, the measurements in said column a being given ininches and hundredths of an inch, and a third column a of numeralsgiving the lengths of the rafters for the several pitches in feet andhundredths of feet. Hence when the lengths of run and the total rise ofa given rafter are known the rise in inches per foot of run can bereadily determined by the ordinary process of division. When the resultis applied to the scale and the length of run of the rafter ismultiplied by the numeral in the col umn a opposite the numeralrepresenting the rise per foot, the length of said given rafter will beattained The scale A also includes for each numeral representing rise aninclined line, (designated by the reference letter 01. said linesrepresenting the vertical or upper terminal cuts of the rafters havingthe respective pitches designated by the numerals contiguous to whichthey are arranged. When a miter-bevel is applied to the scale with itsstock in contact with the edge of the arm A and its blade in alinementwith the inclined line a contiguous to the numeral in the column a whichindicates the rise of the rafter, said miter-bevel will indicate the cutof the upper extremity of the rafter or that portion which is jointed tothe ridge-piece. In the same Way a bevel-scale B is arranged at one ofthe forty-five-degree angles of the triangle, the same consisting of aseries of radiating lines marked, respectively, to correspond with thenumerals of the column a, as 2, 3, 4, (inc. and by applying themiterbevel to the scale B the adjustment thereof necessary for formingthe lower or horizontal cut of the given rafter is secured, said loweror horizontal out being that which provides the desired bearing of therafter upon the plate. Upon the other perpendicular arm O of thetriangle is arranged a scale corresponding with that upon the arm A inthat it contains columns 0, c, and c of figures representing,respectively, the rise, length in inches per foot of run, and length infeet per foot of run of hip and valley rafters, said scale alsoincluding inclined lines o to indicate the upper 01' vertical cuts ofsaid rafters. In connection with the scale on the arm 0 is a scale D,preferably formed at the other forty-fivedegree angle and consisting ofa plurality of radiating lines marked to correspond with the numerals inthe column 0, indicating the rise of hip and valley rafters. The scales0 and D are used in the same manner as described in connection with thescales A and B. Upon the reverse side of the'tool is arranged a scale E,consisting of a plurality of inclined lines e, designated by numerals 2,3, 4, &c., indicating rise per foot of run and corresponding,respectively, with the numerals in the column 0, said inclined linesdesignating the transverse miter or bevel of the hip or valley rafter tofit the ridge-piece. F represents another scale, also con sistin g of aseries of inclined lines, designated by numerals 2, 3, and 4,representing rise to a foot per run and adapted to indicate thetransverse bevel of jack-rafters to fit the hip-rafters hav-' ing agiven rise.

By the use of a device of the class described, which may be made ofmetal or any other suitable material, the measurementand terminal bevelsof the various timbers used in roof-framing may be determined withoutbeing familiar with the art and without the trial necessary when theaccurate measurements are unknown.

As will be seen from the foregoing description, the convergent linesarranged at each of the acute angles of the square are designated by acharacter corresponding with a character upon one of the inclined linesat the opposite perpendicular side of the square, the lines at the angleand side which are designated by corresponding characters being inalinement. This alinement of the inclined lines is due to the fact thatthe terminal cuts of a rafter are presumed to be perpendicular to eachother. Hence any variation of aline at the angle from a verticalposition will cause a corresponding variation of the relative line atthe opposite side. The reason that lines disposed at the same angle orrespectively in alinement with each other will give the angles,respectively, for the upper and lower ends of a rafter is that bydisposing said lines, respectively, contiguous to one side and theopposite angle of the triangle the measurements of the angles are taken,respectively, from perpendioularly-disposed sides of the triangle. It isobvious that the cuts at the opposite ends of a rafter must beperpendicular to each other no matter what the pitch of that rafter maybe.

The rise and length characters, which are arranged, respectively, in thecolumns a and a for common rafters and in the columns 0 and c for hipand valley rafters, are disposed contiguous to and are designed to des-'ignate each of the inclined lines which are located on one side of thetriangle and which have a common point of convergence, while the alinedlines at the opposite angle of the triangle are preferably designatedsimply by the rise characters.

Various changes in the form, proportion, and the minor details ofconstruction may be resorted to without departing from the spirit orsacrificing any'of the advantages of this invention.

Having described my invention, what I claim is As an article ofmanufacture, a roof-framing tool comprising a body, of a rightangledtriangular form, provided on one of its sides with a series of parallelcolumns extending longitudinally thereof and containing charactersdesignating the rise of a rafter per unit A of run, and the lengththereof in inches and feet, and a series of transverse lines arrangedadjacent to the characters in such columns, intersecting the latter, andconverging to the opposite point or angle of the triangle to give theproper bevel or angle of the plumb cut at one end of the rafter; and anisolated group or scale of convergent lines arranged ad jacent to thepoint or angle to which the transverse lines across said columnsconverge, said isolated lines being also arranged in alinement with thetransverse lines and designated by the same characters as the latter toprovide for indicating the angle or bevel of the cut at the opposite endof the same rafter, substantially as described.

In testimony that I claim the foregoing as my own I have hereto affixedmy signature in the presence of two witnesses.

GEORGE CRANE THOMPSON.

YVitnesses:

FRED CHAPPELL, FRANCIS A. ABBOTT.

